1. Field of the Invention
The present invention relates to an image forming system and method, and more particularly to an image forming system and method using an image processing unit to which an optional paper feed unit or an optional paper output unit is connected.
2. Description of the Related Art
Conventionally, technology of a printer system has been proposed in which an optional paper feed unit or optional paper output unit is connected to an image forming apparatus. In such a system, when useless residual paper is present on a paper conveying path at power-on or before jam recovery, or when residual paper remains over a plurality of units, automatic paper output of the useless residual paper is started by carrying out paper conveyance operation of the individual units. Thus, the residual paper is automatically ejected to the outside of the apparatus accurately without causing undesirable damage to the residual paper (for example, see Japanese Patent Application Laid-open Nos. 09-011559/1997 and 09-104141/1997).
In the conventional technology, however, if the residual paper remains at a place where paper detecting sensors on the conveying path of the units cannot detect the residual paper even if it extends over the plurality of units, a condition occurs in which the units cannot start the conveyance operation at the same time. Accordingly, pulling or pushing of the residual paper occurs between the units, which can cause damage to both the residual paper and units. This hinders smooth automatic paper output, thereby presenting a problem in that a user must remove the residual paper to be ejected automatically as jam paper.
In addition, the check operation of the residual paper or the start or stop of the automatic paper output is not synchronized between the units. This offers a problem of excessive driving of the conveying path of the units, or of hindering the residual paper from being ejected to the outside without fail.
The present invention is implemented to solve the foregoing problems. It is therefore an object of the present invention to improve the usability by reducing the initializing time period of the apparatus by optimizing the detection processing of the residual paper in the apparatus at power-on or jam recovery and the timing of the start and stop processing of the automatic paper output.